The present invention relates generally to apparatus and methods for producing waveforms of musical tones, voices or other sounds on the basis of waveform data supplied from memory or the like, and more particularly to an improved waveform producing apparatus and method capable of producing waveforms that faithfully represent tone color variations effected by a player using various styles of rendition (i.e., performing techniques) or various sorts of articulation unique to a natural musical instrument. It should be appreciated that the basic principles of the present invention can be applied extensively to every type of equipment, apparatus and methods having the function of generating musical tones, voices or any other sounds, such as automatic performance devices, computers, electronic game devices and multimedia-related devices, not to mention electronic musical instruments. Also, let it be assumed that the terms xe2x80x9ctone waveformxe2x80x9d in this specification are not necessarily limited to a waveform of a musical tone alone and are used in a much broader sense that may embrace a waveform of a voice or any other type of sound.
The so-called xe2x80x9cwaveform memory readoutxe2x80x9d technique has already been well known, which prestores waveform data (i.e., waveform sample data) coded in a given coding scheme, such as the PCM (Pulse Code Modulation), DPCM (Differential Pulse Code Modulation) or ADPCM (Adaptive Differential Pulse Code Modulation), and then reads out the thus-prestored waveform data at a rate corresponding to a desired tone pitch to thereby produce a tone waveform. So far, various types of xe2x80x9cwaveform memory readoutxe2x80x9d technique have been proposed and known in the art, most of which are directed to producing a waveform covering from the start to end of a tone. As one specific example of the waveform memory readout technique, there has been known a scheme of prestoring waveform data of a complete waveform of a tone covering from the start to end thereof. As another example of the waveform memory readout technique, there has been known a scheme of prestoring waveform data of a complete waveform only for a particular portion, such as an attach portion, of a tone presenting relatively complex variations and prestoring a predetermined loop waveform for a sustain portion and the like presenting less variations. In this patent specification, the terms xe2x80x9cloop waveformxe2x80x9d are used to refer to a waveform to be read out repeatedly, i.e., in a looped fashion.
With the conventional waveform memory readout scheme of prestoring waveform data of a complete waveform of a tone covering from the start to end thereof or prestoring waveform data of a complete waveform only for a particular portion, such as an attach portion, of a tone, however, it has been necessary to prestore a great number of various waveform data corresponding to a variety of styles of rendition (or various sorts of articulation), which would undesirably require a large storage capacity.
Further, although the above-mentioned scheme of prestoring waveform data of a complete waveform of a tone can faithfully express tone color variations effected using various styles of rendition (or various sorts of articulation) unique to a natural musical instrument, it can only reproduce the tone in just the same way as the prestored waveform data and thus would afford very poor controllability and editability. For instance, with this waveform memory readout scheme, it has been extremely difficult to control time-axial and other characteristics of the waveform data, corresponding to a desired style of rendition (or sort of articulation), in accordance with performance data.
It is therefore an object of the present invention to provide a waveform producing method and apparatus which can produce high-quality waveform data corresponding to a variety of styles of rendition (or various sorts of articulation) in a simplified manner with greatly increased facility and controllability.
In order to accomplish the above-mentioned object, the present invention provides a waveform producing method which comprises the steps of: receiving style-of-rendition identification information representing a style of rendition of a performance tone; referring to a predetermined table on the basis of the received style-of-rendition identification information and thereby obtaining, from the predetermined table, style-of-rendition module data corresponding to the received style-of-rendition identification information; and producing a waveform on the basis of the style-of-rendition module data obtained from the predetermined table.
In the present invention, by referring to the predetermined table (i.e., style-of-rendition table), style-of-rendition module data corresponding to the received style-of-rendition identification information is obtained from the table storing a number of style-of-rendition module data usable for producing waveforms corresponding to various styles of rendition. Then, a waveform having characteristics of the style of rendition represented by the style-of-rendition identification information is produced on the basis of the obtained style-of-rendition module data. With such an arrangement that style-of-rendition module data is obtained from the predetermined table (i.e., style-of-rendition table) and then a waveform is produced on the basis of the obtained style-of-rendition module data, the present invention allows a waveform corresponding to any desired style of rendition to be produced in a simplified manner with great facility.
For example, the style-of-rendition identification (ID) information may be supplied, according to the characteristics of the style of rendition of the performance tone, in correspondence with a partial tone segment such as an attack, body or release portion, or in correspondence with a link or joint segment between adjoining tones such as a slur, or in correspondence with a specially performed tone segment such as a vibrato, or in correspondence with a plurality of notes constituting a phrase. Namely, given style-of-rendition identification (ID) information is supplied in accordance with a performance to be reproduced. In the present invention, once such style-of-rendition identification (ID) information is received, style-of-rendition module data for producing a waveform representing the style of rendition is obtained from the table in accordance with the received style-of-rendition identification information.
For example, the style-of-rendition module data is data representing behavior of a waveform to be produced in accordance with a style of rendition. The behavior of the waveform can be defined by various waveform factors. The style-of-rendition module data may include any of time factors such as a time length of a waveform section corresponding to the style-of-rendition module and note-on timing, note-off timing and the like in the waveform section. The style-of-rendition module data may include data representing characteristic behavior of vectors that control the waveform to be reproduced. Here, the vectors correspond, for example, to various fundamental waveform factors for producing the waveform, such as a waveform shape (that determines a tone color or timbre), pitch variation over time and amplitude variation over time, and the vectors of these waveform factors will hereinafter be called a waveform shape vector, pitch vector and amplitude vector, respectively. Time vector representing a progression of the time axis of the waveform may also be used. The respective time axes of the waveform shape vector, pitch vector, amplitude vector, etc. can be controlled in accordance with the time vector. The data representing characteristic behavior of vectors that control the waveform to be reproduced may, for example, be one designating a desired waveform shape vector, pitch vector, amplitude vector, time vector, etc.
According to the present invention, the waveform producing method may further comprise a step of causing style-of-rendition module data to be additionally stored into the predetermined table. The waveform producing method may also comprise a step of deleting desired style-of-rendition module data from the predetermined table. The waveform producing method may also comprise a step of editing the style-of-rendition module data. Further, the above-mentioned step of producing a waveform may include a step of creating a stream of vector data for controlling characteristics of a waveform to be produced on the basis of the style-of-rendition module data. This way, a plurality of vector data can be generated in a time serial manner as a data stream, on the basis of which there can be produced a waveform having tonal characteristics rich in time variation characteristics and controllability.
The present invention also provides a waveform producing method which comprises the steps of receiving style-of-rendition data representing a style of rendition of a performance tone; referring to a predetermined table on the basis of the received style-of-rendition data and thereby obtaining, from the predetermined table, waveform factor data corresponding to the received style-of-rendition data; modifying a waveform factor corresponding to the waveform factor data obtained from the predetermined table, in accordance with the received style-of-rendition data; and producing a waveform on the basis of the modified waveform factor. Because the waveform factor corresponding to the waveform factor data obtained from the table can be modified and a waveform can be produced on the basis of the modified waveform factor, the present invention allows style-of-rendition waveforms rich in variations to be produced with a simplified structure and enhanced controllability.
When no waveform factor data corresponding exactly to the value of the style-of-rendition data is contained in the predetermined table, the above-mentioned step of referring obtains, from the predetermined table, alternative waveform factor data approximate to the value of the style-of-rendition data, and then the above-mentioned step of modifying modifies the content of a waveform factor corresponding to the alternative waveform factor data so as to approach the content that corresponds exactly to the value of the style-of-rendition data. Then, even when waveform factor data corresponding exactly to the value of the designated style-of-rendition data can not be obtained from the predetermined table, an appropriate style-of-rendition waveform can be produced by modifying the alternative waveform factor data as necessary.
The present invention may be constructed and implemented not only as the method invention as discussed above but also as an apparatus invention. Also, the present invention may be arranged and implemented as a software program for execution by a processor such as a computer or DSP, as well as a storage medium storing such a program. Furthermore, the processor used in the present invention may comprise a dedicated processor based on predetermined fixed hardware circuitry, rather than a general-purpose type processor capable of running software.